Why are plants and animals in the Persian Gulf less varied than those in other parts of the Indian Ocean?

The variety of plants and animals in the Persian Gulf is more limited than in other parts of the Indian Ocean primarily due to the region's extreme environmental conditions.1

Specifically, the gulf experiences high water temperatures and high levels of salinity. These conditions are driven by a combination of high evaporation rates, which exceed the limited freshwater inflow from rivers, and the shallow nature of the basin. While the gulf supports a variety of marine life, these harsh physical factors lead to a noticeable diminution in the diversity of flora and fauna compared to the broader Indian Ocean ecosystem.213